There have been numerous storage devices developed for holding small rectangular objects like tape cassettes or compact discs that are contained in individual storage boxes. Many of these devices are formed with dividers that define individual compartments in which each storage box is held. A disadvantage of these devices is that space occupied by the dividers cannot contain a storage box. This reduces the capacity of these devices. Still another disadvantage of these systems is that the dividers restrict the lateral movement of the storage boxes held therein. This makes it impossible to move a set of the storage boxes laterally across the device so as to create a space for a third box between two already stored boxes. Consequently, a person wishing to so interleave the storage boxes must move each of the boxes individually in order to create the necessary opening.